Imaging Manifestations Of Metanephric Adenoma: A Report Of 2 Cases And A Literature Review

Our objective is to summarize the characteristic imaging manifestations of metanephric adenoma (MA) and to improve the diagnosis of MA. The imaging and clinical data of two cases with pathologically confirmed MA in our hospital were analyzed, retrospectively. The literature reports and characteristic imaging manifestations of the disease were discussed. MA is typically unilateral and accompanied by polycythemia. We found that the main body of the tumor is outside the kidney outline. The tumor is round with smooth edges. CT scans show an equal or low density, and the internal density can be uniform or uneven. Some cases are accompanied by calcification and cystic degeneration. Enhanced-CT scanning shows a mild to moderate progressive enhancement. MA presents as a hypoechoic mass on ultrasound examination. Color Doppler flow imaging (CDFI) shows a minimal blood flow echo. So we can see the imaging manifestations of MA show specific characteristics. When the main body of the tumor is located outside the outline of the kidney, the mass shows a mild to moderate progressive enhancement or a delayed enhancement after contrast-enhanced scanning. When a renal tumor with polycythemia is encountered, MA should be suspected.